[clang] [HLSL] Add StructuredBuffer to external sema source (PR #106316)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `clang` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/4928

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: AST/HLSL/StructuredBuffer-AST.hlsl' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 1: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/clang/20/include -nostdsysteminc -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump -DEMPTY /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl | /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck -check-prefix=EMPTY /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck -check-prefix=EMPTY /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/clang/20/include -nostdsysteminc -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump -DEMPTY /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
RUN: at line 2: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/clang/20/include -nostdsysteminc -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl | /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/clang/20/include -nostdsysteminc -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl:33:16: error: CHECK-NEXT: expected string not found in input
// CHECK-NEXT: FieldDecl 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> <invalid sloc> implicit h 'element_type *'
               ^
<stdin>:33:63: note: scanning from here
| | |-FinalAttr 0x559cfdc41e78 <<invalid sloc>> Implicit final
                                                              ^
<stdin>:34:6: note: possible intended match here
| | |-FieldDecl 0x559cfdc5d5e8 <<invalid sloc>> <invalid sloc> implicit h 'element_type * [[hlsl::resource_class(UAV)]]':'element_type *'
     ^

Input file: <stdin>
Check file: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/test/AST/HLSL/StructuredBuffer-AST.hlsl

-dump-input=help explains the following input dump.

Input was:
<<<<<<
           1: TranslationUnitDecl 0x559cfdc19b38 <<invalid sloc>> <invalid sloc> 
           2: |-NamespaceDecl 0x559cfdc1a458 <<invalid sloc>> <invalid sloc> implicit hlsl 
           3: | |-TypeAliasTemplateDecl 0x559cfdc1a7b0 <<invalid sloc>> <invalid sloc> implicit vector 
           4: | | |-TemplateTypeParmDecl 0x559cfdc1a4e0 <<invalid sloc>> <invalid sloc> class depth 0 index 0 element 
           5: | | | `-TemplateArgument type 'float' 
           6: | | | `-BuiltinType 0x559cfdc19d40 'float' 
           7: | | |-NonTypeTemplateParmDecl 0x559cfdc1a5e0 <<invalid sloc>> <invalid sloc> 'int' depth 0 index 1 element_count 
           8: | | | `-TemplateArgument expr '4' 
           9: | | | `-IntegerLiteral 0x559cfdc1a638 <<invalid sloc>> 'int' 4 
          10: | | `-TypeAliasDecl 0x559cfdc1a750 <<invalid sloc>> <invalid sloc> implicit vector 'vector<element, element_count>' 
          11: | | `-DependentSizedExtVectorType 0x559cfdc1a700 'vector<element, element_count>' dependent <invalid sloc> 
          12: | | |-TemplateTypeParmType 0x559cfdc1a560 'element' dependent depth 0 index 0 
          13: | | | `-TemplateTypeParm 0x559cfdc1a4e0 'element' 
          14: | | `-DeclRefExpr 0x559cfdc1a698 <<invalid sloc>> 'int' lvalue NonTypeTemplateParm 0x559cfdc1a5e0 'element_count' 'int' 
          15: | |-ClassTemplateDecl 0x559cfdc1a9a8 <<invalid sloc>> <invalid sloc> implicit RWBuffer 
          16: | | |-TemplateTypeParmDecl 0x559cfdc1a908 <<invalid sloc>> <invalid sloc> class depth 0 index 0 element_type 
          17: | | `-CXXRecordDecl 0x559cfdc1a808 <<invalid sloc>> <invalid sloc> implicit <undeserialized declarations> class RWBuffer 
          18: | | `-FinalAttr 0x559cfdc1a8b0 <<invalid sloc>> Implicit final 
          19: | |-ClassTemplateDecl 0x559cfdc41b98 <<invalid sloc>> <invalid sloc> implicit RasterizerOrderedBuffer 
          20: | | |-TemplateTypeParmDecl 0x559cfdc41b00 <<invalid sloc>> <invalid sloc> class depth 0 index 0 element_type 
          21: | | `-CXXRecordDecl 0x559cfdc41a00 <<invalid sloc>> <invalid sloc> implicit <undeserialized declarations> class RasterizerOrderedBuffer 
          22: | | `-FinalAttr 0x559cfdc41aa8 <<invalid sloc>> Implicit final 
...

```

</details>

https://github.com/llvm/llvm-project/pull/106316